The Cave of Swallows, also called the Cave of the Swallows ( es, Sótano de las Golondrinas), is an open-air

pit cave A pit cave, shaft cave or vertical cave—or often simply called a pit (in the US) and pothole or pot (in the UK); jama in South Slavic languages scientific and colloquial vocabulary (borrowed since early research in the Western Balkan Dinaric ...

in the municipality of

Aquismón Aquismón is a town and municipality in San Luis Potosí in central Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United St ...

San Luis Potosí San Luis Potosí (), officially the Free and Sovereign State of San Luis Potosí ( es, Estado Libre y Soberano de San Luis Potosí), is one of the 32 states which compose the Federal Entities of Mexico. It is divided in 58 municipalities and i ...

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

. The elliptical mouth, on a slope of

karst Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant ro ...

, is 49 by 62 m wide and is undercut around all of its perimeter, widening to a room approximately 303 by 135 meters (994 by 442 ft) wide. The floor of the cave is a 333-meter (1,092 ft) freefall drop from the lowest side of the opening, with a 370-meter (1,214 ft) drop from the highest side, making it the largest known cave shaft in the world, the second deepest pit in Mexico and perhaps the 11th deepest sheer drop in the world.

List of deepest caves This list of deepest caves includes the deepest known natural caves according to maximum surveyed depth . The depth value is measured from the highest to the lowest accessible cave point. See also *List of caves *List of deepest mines * List o ...

uses different criteria, not sheer drop but accessibility.

History

The cave has been known to the local

Huastec people The Huastec or Téenek (contraction of ''Te' Inik'', "people from here"; also known as Huaxtec, Wastek or Huastecos) are an indigenous people of Mexico, living in the La Huasteca region including the states of Hidalgo, Veracruz, San Luis Potos� ...

since ancient times. T. R. Evans, Charles Borland and Randy Sterns were first shown the cave on 27 December 1966. The first documented descent was on 4 April 1967.

Geology

The cave is formed in the El Abra and Tamabra formations, limestones of Middle Cretaceous age. The cave's speleogenesis is still not fully known but is a result of solutional enlargement along a vertical fracture, with subsequent vadose enlargement.

Etymology

The cave's Spanish name ''Sótano de las Golondrinas'' means ''Basement of the Swallows'', owing to the many birds which live in holes on the cave walls. These are mostly

white-collared swift The white-collared swift (''Streptoprocne zonaris'') is a species of bird in subfamily Cypseloidinae of the swift family Apodidae. It is found in Mexico, the Greater and Lesser Antilles, Trinidad, and every mainland South America country excep ...

s (''vencejos'' in Spanish) and

green parakeet The green parakeet (''Psittacara holochlorus'') is a medium-sized parrot occurring in North and Central America, from the southernmost tip of Texas south to northern Nicaragua. Description The green parakeet is 32 cm in length, and is mos ...

s (''periquillo quila''). Actual

swallow The swallows, martins, and saw-wings, or Hirundinidae, are a family of passerine songbirds found around the world on all continents, including occasionally in Antarctica. Highly adapted to aerial feeding, they have a distinctive appearance. The ...

s are in fact rarely found here. Each morning, flocks of birds exit the cave by flying in concentric circles, gaining height until they reach the entrance. In the evenings a large flock of swifts circles the mouth of the cave and about once each minute, a group of perhaps 50 breaks off and heads straight down towards the opening. When they cross the edge, the birds pull in their wings and free-fall, extending their wings and pulling out of the dive when they reach the heights of their nests. Watching this has become popular with tourists.

Description

Temperatures in the cave are low.

Vegetation Vegetation is an assemblage of plant species and the ground cover they provide. It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic character ...

grows thickly at the mouth, The cave floor is covered with a thick layer of debris and

guano Guano (Spanish from qu, wanu) is the accumulated excrement of seabirds or bats. As a manure, guano is a highly effective fertilizer due to the high content of nitrogen, phosphate, and potassium, all key nutrients essential for plant growth. G ...

. The fungi in the guano may cause

histoplasmosis Histoplasmosis is a fungal infection caused by ''Histoplasma capsulatum''. Symptoms of this infection vary greatly, but the disease affects primarily the lungs. Occasionally, other organs are affected; called disseminated histoplasmosis, it can ...

in humans. The cave floor and walls are inhabited by millipedes, scorpions, insects, snakes and birds. At the floor -- already below sea level -- at the bottom of the main shaft there is a series of narrow pits known as "The Crevice", totaling some , which brings the total depth of the cave to . This would put that the lowest accessible point at more than 300 meters below sea level.

Extreme sports tourism

The cave is a popular

vertical caving A pit cave, shaft cave or vertical cave—or often simply called a pit (in the US) and pothole or pot (in the UK); jama in South Slavic languages scientific and colloquial vocabulary (borrowed since early research in the Western Balkan Dinaric A ...

destination.

Caver Caving – also known as spelunking in the United States and Canada and potholing in the United Kingdom and Ireland – is the recreational pastime of exploring wild cave systems (as distinguished from show caves). In contrast, speleology is ...

s anchor their ropes on the low side, where bolts have been installed in the rock and the area is clear of obstructions. Rappelling to the floor can take up to an hour. Climbing back out may take from forty minutes to more than two hours. A person without a

parachute A parachute is a device used to slow the motion of an object through an atmosphere by creating drag or, in a ram-air parachute, aerodynamic lift. A major application is to support people, for recreation or as a safety device for aviators, who ...

would take almost ten

second The second (symbol: s) is the unit of time in the International System of Units (SI), historically defined as of a day – this factor derived from the division of the day first into 24 hours, then to 60 minutes and finally to 60 seconds ...

s to freefall from the mouth to the floor, hence the pit is also popular with

extreme sport Action sports, adventure sports or extreme sports are activities perceived as involving a high degree of risk. These activities often involve speed, height, a high level of physical exertion and highly specialized gear. Extreme tourism overl ...

s enthusiasts for BASE jumping. BASE jumpers can get out in about 10 minutes using a winch.

References

External links

* {{DEFAULTSORT:Cave Of Swallows Caves of Mexico Limestone caves Landforms of San Luis Potosí Wild caves Sinkholes of Mexico Karst formations of Mexico